import random

def shuffle(lol, seed):
    '''
    lol :: list of list as input
    seed :: seed the shuffling

    shuffle inplace each list in the same order
    '''
    for l in lol:
        random.seed(seed)
        random.shuffle(l)

def minibatch(l, bs):
    '''
    l :: list of word idxs
    return a list of minibatches of indexes
    which size is equal to bs
    border cases are treated as follow:
    eg: [0,1,2,3] and bs = 3
    will output:
    [[0],[0,1],[0,1,2],[1,2,3]]
    '''
    out  = [l[:i] for i in xrange(1, min(bs,len(l)+1) )]
    out += [l[i-bs:i] for i in xrange(bs,len(l)+1) ]
    assert len(l) == len(out)
    return out

def contextwin(l, win):
    '''
    win :: int corresponding to the size of the window
    given a list of indexes composing a sentence
    it will return a list of list of indexes corresponding
    to context windows surrounding each word in the sentence
    '''
    assert (win % 2) == 1
    assert win >=1
    l = list(l)

    lpadded = win/2 * [-1] + l + win/2 * [-1]
    out = [ lpadded[i:i+win] for i in range(len(l)) ]

    assert len(out) == len(l)
    return out
'''
>>> x
    array([0, 1, 2, 3, 4], dtype=int32)
>>> contextwin(x, 3)
    [[-1, 0, 1],
    [ 0, 1, 2],
    [ 1, 2, 3],
    [ 2, 3, 4],
    [ 3, 4,-1]]
>>> contextwin(x, 7)
    [[-1, -1, -1, 0, 1, 2, 3],
    [-1, -1,  0, 1, 2, 3, 4],
    [-1,  0,  1, 2, 3, 4,-1],
    [ 0,  1,  2, 3, 4,-1,-1],
    [ 1,  2,  3, 4,-1,-1,-1]]
 '''

